原生JS實現圖片拖拽移動與縮放
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
<style>
#box {
width: 100px;
height: 100px;
background-color: aquamarine;
position: absolute;
}
#father {
width: 600px;
height: 500px;
background-color: rgb(226, 117, 184);
position: relative;
}
img {
width: 100%;
height: 100%;
cursor: move;
}
#scale {
width: 10px;
height: 10px;
overflow: hidden;
cursor: se-resize;
position: absolute;
right: 0;
bottom: 0;
background-color: rgb(122, 191, 238);
}
</style>
</head>
<body>
<div id="father">
<div id="box">
<img src="http://img4.imgtn.bdimg.com/it/u=4245161611,1195625695&fm=27&gp=0.jpg"/>
<div id="scale"></div>
</div>
</div>
<script type="text/javascript">
// box是裝圖片的容器,fa是圖片移動縮放的範圍,scale是控制縮放的小圖標
var box = document.getElementById("box");
var fa = document.getElementById(‘father‘);
var scale = document.getElementById("scale");
// 圖片移動效果
box.onmousedown=function(ev) {
var oEvent = ev;
// 瀏覽器有一些圖片的默認事件,這裏要阻止
oEvent.preventDefault();
var disX = oEvent.clientX - box.offsetLeft;
var disY = oEvent.clientY - box.offsetTop;
fa.onmousemove=function (ev) {
oEvent = ev;
oEvent.preventDefault();
var x = oEvent.clientX -disX;
var y = oEvent.clientY -disY;
// 圖形移動的邊界判斷
x = x <= 0 ? 0 : x;
x = x >= fa.offsetWidth-box.offsetWidth ? fa.offsetWidth-box.offsetWidth : x;
y = y <= 0 ? 0 : y;
y = y >= fa.offsetHeight-box.offsetHeight ? fa.offsetHeight-box.offsetHeight : y;
box.style.left = x + ‘px‘;
box.style.top = y + ‘px‘;
}
// 圖形移出父盒子取消移動事件,防止移動過快觸發鼠標移出事件,導致鼠標彈起事件失效
fa.onmouseleave = function () {
fa.onmousemove=null;
fa.onmouseup=null;
}
// 鼠標彈起後停止移動
fa.onmouseup=function() {
fa.onmousemove=null;
fa.onmouseup=null;
}
}
// 圖片縮放效果
scale.onmousedown = function (e) {
// 阻止冒泡,避免縮放時觸發移動事件
e.stopPropagation();
e.preventDefault();
var pos = {
‘w‘: box.offsetWidth,
‘h‘: box.offsetHeight,
‘x‘: e.clientX,
‘y‘: e.clientY
};
fa.onmousemove = function (ev) {
ev.preventDefault();
// 設置圖片的最小縮放為30*30
var w = Math.max(30, ev.clientX - pos.x + pos.w)
var h = Math.max(30,ev.clientY - pos.y + pos.h)
// console.log(w,h)
// 設置圖片的最大寬高
w = w >= fa.offsetWidth-box.offsetLeft ? fa.offsetWidth-box.offsetLeft : w
h = h >= fa.offsetHeight-box.offsetTop ? fa.offsetHeight-box.offsetTop : h
box.style.width = w + ‘px‘;
box.style.height = h + ‘px‘;
// console.log(box.offsetWidth,box.offsetHeight)
}
fa.onmouseleave = function () {
fa.onmousemove=null;
fa.onmouseup=null;
}
fa.onmouseup=function() {
fa.onmousemove=null;
fa.onmouseup=null;
}
}
</script>
</body>
</html>
原生JS實現圖片拖拽移動與縮放